<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="jquery.js"></script>
</head>
<body>
<div id="app"></div>
<input type="button" value="button" onclick="btnClick()">
<script>
    function btnClick() {
        $.get("http://localhost:8080/hello",function (msg) {
            alert(msg);
        })
    }
</script>
</body>
</html>